RIVERSIDE, CA — A woman accused of killing her 2-year-old son at their Eastvale home must stand trial on charges of first-degree murder and assault on a child resulting in great bodily injury or death, a judge ruled Wednesday.
Xiu Xiu Sun, 35, allegedly killed Chris Cui in October 2022.
Following a preliminary hearing Wednesday, Riverside County Superior Court Judge Timothy Freer found there was sufficient evidence to bound Sun over for trial on the felony counts.
The judge scheduled a post-preliminary hearing arraignment for Sept. 10 at the Riverside Hall of Justice.
The defendant remains held in lieu of $1 million bail at the Robert Presley Detention Center.
During court proceedings more than two years ago, Sun's public defender submitted motions arguing that she was psychologically unstable and required mental health treatment. After psychiatric evaluations that continued through most of 2023, a judge ruled Sun should undergo treatment, and she was committed to a state hospital.
However, in late 2024, a judge reviewed the case and determined that Sun's "mental competency had been restored," according to the District Attorney's Office.
Sheriff's Sgt. Steve Brosche said patrol deputies were called to the defendant's and her husband's residence in the 6000 block of Rosewood Way, near Turnberry Place, on the morning of Oct. 20, 2022, to investigate reports of an injured child.
Brosche said deputies arrived to find paramedics trying to resuscitate Chris, who had suffered unspecified injuries.
"After life-saving measures were unsuccessful, the juvenile was pronounced dead at the scene," Brosche said at the time. "During the course of the investigation, foul play was suspected surrounding the juvenile's death."
Brosche said Central Homicide Unit detectives took over the investigation, questioning both Sun and her husband, whose name was not released.
Sun was taken into custody without incident at the sheriff's Jurupa Valley Station, and her husband was allowed to leave, without suspicion of involvement in the toddler's death, according to Brosche.
Details regarding the circumstances behind the fatality, including a possible motive, were not released.
Sun has no documented prior felony convictions in Riverside County.
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